I've got a problem with the idle on my '73 1800ES, the idle is extremely uneven. What I mean by this is that I cannot get the idle to be consistent. I do not mean that when I am at a stop light that the idle goes up and down. My idle stays in one place at each stop light. It is just that the idle setting seems to have a mind of it's own. Sometimes, even after it is hot, the idle will jump up above 1500 rpm. Then later in the day, or the next time I start it up it drops as low as 250 rpm. Naturally I've tried to amend this by adjusting the idle with the idle adjust screw beneath the intake manifold, but it doesn't matter. My idle setting has a mind of it's own. My car has also dropped down to about 15 mpg, I was getting 25 and now... I suspect that it could be the cold start injector. How do I test to see if this is faulty? Since my idle does not run fast consistently could it be something else? I thought that when a cold start injector stops closing that it stays open. I don't know what else it could be besides the cold start injector. Please help me.